Consolidation des digues Kinderdijk Schoonhovenseveer (KIS)

Les digues sont indissociables du paysage néerlandais. Leur fonction initiale, à savoir la protection du pays contre les inondations, comme celle de 1953, se combine aujourd’hui à l’intégration dans le paysage, aux activités récréatives et à la préservation de la nature. Cela rend la tâche des 23 administrations néerlandaises des eaux (« Waterschap ») d’autant plus pertinente. Elles sont responsables de l’entretien des centaines de kilomètres de digues. Le Waterschap Rivierenland - responsable des digues en Gueldre, en Hollande méridionale, dans le Brabant septentrional et à Utrecht - a consolidé la Lekdijk en 2013 afin de satisfaire aux exigences de sécurité. 

Solution & Result

Traditionally dikes are reinforced with local material. In some places the soil is too weak for this, and the deeper sand layers shift under the pressure of the water. In Streefkerk this caused a displacement of the dike in the 80s at high tide, with houses at the foot of the embankment pushed backwards several metres.

Design work: a gleaming success

Om de veiligheid bij een hoge waterstand te garanderen, integreerde BESIX boorpalen en diepwanden in de diepere grondlagen van de dijk. Als de dijk zelf zou bezwijken, houdt de diepwand alsnog het water tegen.

Aangezien de toepassing van deze techniek voor dijkversterking nagelnieuw was, werd het ontwerp ook door een team van externe experts bestudeerd. De vernieuwde dijk moet zich immers gedurende honderd jaar probleemloos van zijn taak kunnen kwijten. Het ontwerp van BESIX slaagde met vlag en wimpel.

Inventive techniques protect neighbouring homes

The biggest concern when building the dike reinforcement was the danger of damage to neighbouring homes. The vulnerability of the environment, combined with the gigantic size of the machines to be used, required enormous precision and care from the contractor.

To safeguard the houses as far as possible, BESIX subsidiary Franki Foundations placed vibration-free bored piles and diaphragm walls. The placing also took place in several phases spread over a year, so as to minimize the stress on the soft subsoil. In this way the dike wall was placed without damaging the surrounding homes.

Good cooperation with external experts

'Collaboration with the water board’s experts was very constructive,' says dikes expert Christophe Bauduin (BESIX). 'The experts posed open and honest questions about the design. Strengthening a dike in this way was new to them and BESIX was recognized as an expert here.'

Internal expertise reaches new summits

In its own ranks too, BESIX reaped the fruits of this project. 'We started with a single dikes expert in the company', says Bauduin. 'In the course of the project he was able to share his knowledge with colleagues.' BESIX has since specialized further in dike reinforcement with various reinforcement technologies.

Community impact

'To ensure sufficient public support for the dike reinforcement, we made a priority of our conversations with residents on and around the Lekdijk. We tried as far as possible to fulfil everyone's wishes and desires in the project', says Bram De Fockert, project leader at the Rivierenland water board.

At the request of local residents the strengthening of the dike was combined with the redevelopment of the marina. Space is also provided on the dike for new homes.